|Chord|Root|Major Third|Perfect Fifth|Minor Seventh|
|---|---|---|---|---|
|C7|C|E|G|B♭|
|C♯7|C♯|E♯ (F)|G♯|B|
|D♭7|D♭|F|A♭|C♭ (B)|
|D7|D|F♯|A|C|
|D♯7|D♯|F (G)|A♯|C♯|
|E♭7|E♭|G|B♭|D♭|
|E7|E|G♯|B|D|
|F7|F|A|C|E♭|
|F♯7|F♯|A♯|C♯|E|
|G♭7|G♭|B♭|D♭|F♭ (E)|
|G7|G|B|D|F|
|G♯7|G♯|B♯ (C)|D♯|F♯|
|A♭7|A♭|C|E♭|G♭|
|A7|A|C♯|E|G|
|A♯7|A♯|C (D)|E♯ (F)|G♯|
|B♭7|B♭|D|F|A♭|
|B7|B|D♯|F♯|A|

Question: what's the total number of thirds you can make on a 7th form chord?
Answer: 17